feat (exm): sincos example

exm/sincos.ml

@@ -0,0 +1,44 @@
+
+open Hsim.Types
+open Solvers.Zls
+
+let of_array a = Bigarray.Array1.of_array Bigarray.Float64 Bigarray.c_layout a
+
+type state = { si : bool; sx : carray }
+
+let yd    = cmake 3
+let zout  = cmake 1
+let zsize = 1
+
+let fzer _ _ _ = zout
+let fout _ _ y = of_array [| y.{0}; y.{1}; y.{2} |]
+let cget s     = s.sx
+let cset s lx  = { s with sx = lx }
+let zset s _   = s
+let jump _     = true
+let horizon _  = max_float
+
+let sinus_cosinus theta0 omega =
+  let sin0 = Float.sin theta0 in
+  let cos0 = Float.cos theta0 in
+  let fder _ _ y =
+    yd.{0} <- omega *. y.{1}; yd.{1} <- -.omega *. y.{0}; yd.{2} <- 1.0; yd in
+  let step { si; sx } _ =
+    let sx = if si then of_array [| sin0; cos0; 0.0 |] else sx in
+    of_array [| sx.{0}; sx.{1}; sx.{2} |], { sx; si = false } in
+  let state     = { sx = of_array [| sin0; cos0; 0.0 |]; si = true } in
+  let reset _ _ = state in
+  HNode {
+    state; fder; fzer; fout; step; horizon; cset; cget; zset; zsize; reset; jump 
+  }
+
+let errmsg_invalid = "Invalid arguments to model (needed: 2 floats)"
+let errmsg_few     = "Too few arguments to model (needed: 2 floats)"
+let errmsg_many    = "Too many arguments to model (needed: 2 floats)"
+let sinus_cosinus = function
+  | [t0; om] ->
+      let t0, om = try float_of_string t0, float_of_string om
+      with Failure _ -> raise (Invalid_argument errmsg_invalid) in
+      sinus_cosinus t0 om
+  | [] | [_] -> raise (Invalid_argument errmsg_few)
+  | _        -> raise (Invalid_argument errmsg_many)